PTFE tape or thread tape is an inert tape used by some people for gradual stretching of piercings.
One method for stretching a piercing is by gradually increasing the size of the jewelry. An easy way to do this is by wrapping tape around the jewelry, adding a little bit every few days. One of the main problems with tape—for example electrical tape—is the adhesive leaking out and irritating the piercing. In addition, some people react to the plastics used.
PTFE tape has no adhesive, and is quite thin (allowing very gradual size increases). PTFE tape can be found in the plumbing section of any hardware store.